before hurricanes thomas last year, isaac in august and recently sandy. each storm brought a grim reminder of yet one more ever-present disaster: the deadly cholera epidemic that started ten months after the quake. at the cholera ward of saint luke's hospital just outside the capital port-au-prince, this doctor says since hurricane sandy admissions have doubled from 20 to 40 patients each day. >> most of the new cases are coming from further up the hill in places where we had not seen them before. i'm not positive but perhaps the wells there have been contaminated. >> reporter: experts believe cholera was brought here by u.n. peacekeepers. untreated sewage from this base flowed into a tributary of the river, the major source of water for both washing and drinking. cholera is spread by fecal-oral contact. two years on 200,000 patients have been sickened, 750 d 7,500 have died from diarrhea and fluid loss. each flood brings more contaminated water, more cases. the epidemic prompted massive relief efforts and public campaigns. on the streets and in classroom